Role of Immunohistochemical Studies in Neuroendocrine Tumors of Gastrointestinal Tract.

Neuroendocrine Tumors Of The Gastrointestinal Tract Are Not A Rare Entity. Neuroendocrine Tumors Were Initially Called Apudomas And Were Believed To Be Of Neural Crest Origin. Later The Endodermal Origin Was Established. Due To The Neurotransmitter Like Substance Production The Name Neuroendocrine Tumors Have Remained. These Tumors Occur Anywhere In The Gut With A Higher Incidence In The Large Intestine. Many Attempts Have Been Made To Classify These Tumors. The First Classification Was Based On Topography, Then Histological Pattern, Recently On Immunohistochemical Marker Expression. Amongst The Many Neuroendocrine Markers Chromogranin A, Synaptophysin Are The Most Useful. Most Cases Of Well Differentiated Neuroendocrine Tumors The Diagnosis Is Easily Made From The Histological Appearance. But In Less Well Differentiated Types The Interpretation Poses A Challenge. A Correct Diagnosis Is Required Because Of The Prognostic Implication And Variation In Treatment Modalities. This Work Aims At Confirming Histologically Diagnosed Cases Of Neuroendocrine Tumors And Also Detects Neuroendocrine Differentiation In Otherwise Exocrine And Poorly Differentiated Tumors With The Help Of Immunohistochemical Markers Chromogranin A And Synaptophysin. The Association Between Neuroendocrine Marker Expression And Their Prognostic Implication Has Also Been Studied.